114λ × 0.114 λ × 0.017 λ. The nanoparticles, derived from the CaxCo(0.90-x)Zn0.10Fe2O4
material with varying Ca concentrations (Ca25, Ca50, and Ca75), have
been synthesized using a sol-gel method, and their structural,
morphological, and dielectric properties have been comprehensively characterized. Dielectric constants and loss tangents have been measured over the frequency range of 2–20 GHz. Simulation of the S21
response at 3.43 GHz, 6.50 GHz, 11.49 GHz, and 16.46 GHz has yielded
maximum magnitudes of −52.78 dB, −48.07 dB, −52.16 dB, and −39.37 dB,
respectively. Experimental verification on an FR-4 rigid substrate at
3.28 GHz, 6.58 GHz, 11.76 GHz, and 16.33 GHz has revealed magnitudes of
−25.67 dB, −24.56 dB, −31.13 dB, and −25.17 dB. Finally, when fabricated
on the flexible microwave substrate, the MTM displayed S21 responses of
−48.31 dB, −43.12 dB, −61.80 dB, and −24.70 dB at 3.19 GHz, 6.62 GHz,
11.58 GHz, and 16.65 GHz, respectively. The MTM has exhibited SNG
properties in distinct frequency bands and near-zero index (NZI)
characteristics. The sensitivity, figure of merit (FOM), and Q-factor
have been achieved at 0.096 GHz/RIU, 0.152 GHz/RIU, 0.846 (RIU−1), 0.846 (RIU−1), and 8.430, 29.801, respectively. Its performance has been validated through simulation, VNA measurements, and advanced design system
(ADS) software analysis, showcasing promise for diverse applications in
S-, C-, X-, and Ku-bands. The anticipated structure performs well in
terms of its small size, flexibility, sensitivity, and lightweight,
making it suitable for wireless communications and methanol and ethanol contamination sensing in industrial applications.